Ice growth inhibition by antifreeze proteins.

摘要

A broad range of cold-adapted organisms depend for their survival on the remarkable properties of antifreeze proteins (AFPs). These macromolecular antifreezes inhibit freezing in a non-colligative manner, by blocking the growth of ice crystals. The problem of how they produce this effect poses a challenge at the interface of physics and biology that has engaged researchers for nearly thirty years.; The present study explores both theoretical and experimental aspects of ice growth inhibition by antifreeze proteins. The theoretical component of the work consists of a mathematical model of ice growth inhibition that leads to an expression for the non-equilibrium freezing point depression induced by the adsorption of AFPs at the ice/solution interface. The model treats the case of AFPs adsorbing at random via a kinetic adsorption process.; The experimental component of the work is carried out with the aid of a newly developed apparatus, the temperature gradient thermometer. Three varied applications of this device to the study of AFP/ice interaction are described. First, the kinetics of AFP-induced ice growth inhibition are investigated, enabling comparison with the mathematical model. Second, the controversial question of the reversibility of AFP ice-binding is tested by direct experiment. Third, blood from a number of invertebrate species is screened for antifreeze activity, leading to the discovery of the first AFPs in organisms that are not cold-adapted.{dollar}sp*{dollar} ftn{dollar}sp*{dollar}Originally published in DAI Vol. 59, No. 3. Reprinted here with corrected school.